The present study was undertaken to develop a rapid, quantitative, in vitro system and use it for evaluating antiviral agents, neutralizing antibodies and various cytokine effects on HIV-1 replication. A system was developed to simultaneously test the effects of various agents on 1) the replication of representative strains of HIV, 2) virus transmitted free of cells or associated with cells, and 3) HIV transmitted to T-cells and monocytes. In conjunction with the NIAID/WHO Antibody Serologic Project (ASP), the assay was used to evaluate the potency and strain specificity of controls and purified monoclonal antibodies directed toward V3, V2 gp41, and CD4 binding regions of HIV-1 gp120. I worked with ASP coordinators and analyzed neutralization results for 20 laboratories participating in the study (see D'Souza, Geyer, Hanson, Hendry, Milman and Collaborating Investigators, Evaluation of monoclonal antibodies to HIV-1 envelope by neutralization and binding assays: an international collaboration, AIDS 8:169-181, 1994. In collaboration with Dr. Beaucage (OTRR/DHP/MPS) and Masakazu Koga, the inhibitory effects of modified TAT antisense oligonucleotides are under investigation (see Koga, Geyer, Regan and Beaucage. The synthesis of alternating alpha, Beta oligodeoxyribonucleotides with alternating 3' -3'-and 5' -5'- internucleotic linkages as potential therapeutic agents, Nucleic Acids Symposium Series 29, #3, 1993. In collaboration with Dr. Koga, novel TAT oligonucleotides are being investigated for their potential antiviral properties.